Tool for scraping cylindrical surfaces



.R. D. HEACOX.

TOOL FOR SCRAPING CYLINDRICAL SURFACES.

Patented Nov. 1, 1921 .H m a an 4w I M W 1 WWII/M22 1 ma a D. fl'eac0.3!. 05 5 1 N VEN TOR.

A TTORNEY6 R. D. HEACOX.

TOOL FOR SCRAPING CYLINDRICAL SURFACES.

APPLICATION FlL'ED MAR. 16, 1921.

1,395,823. Patented Nov. 1,- 1921.

- 2 SHEETS-SHEET 2.

INVENTOR.

WW gaw duw A TTORNEY-S NHTED STATES,

PATENT OFFICE.

TOOL FOR SCRAPING GYLINDRIGAL SURFACES.

Application filed March 16, 1921.

To all whom it may concern:

Be it known that I, Ross 1). HnAoox, a citizen of the United States,residing at Washington, in the Districtof Columbia, have inventedcertain new and useful I'mprovements in Tools for. Scraping CylindricalSurfaces; and I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same.

This invention relates to metal working tools and more particularly to ascraper for use in repairing engine cylinders.

The object of the present invention is to provide an improved scraper bymeans of which the interior of an engine cylinder or metal insert placedin the interior surface of an engine cylinder may be scraped to thecorrect contour of the cylinder.

A further object of the present invention is to provide a tool adaptedto be adjusted to the exact contour of the engine cylinder to berepaired.

The invention consists in the novel method and construction, arrangementand combination of parts as hereinafter more particularly described andclaimed.

Two sheets of drawings accompany this specification as part thereof, inwhich like reference characters indicate similar parts throughout.

Figure l is a side elevation of the preferred form of the presentinvention;

Fig. 2 is an end elevation;

Fig. 3 is a top plan view of the device shown in Fig. 1;

Fig. 4 is a vertical medial section of the same device;

. Fig. 5 is a diagrammatic view illustrating the adjustability of thescraper;

Fig. 6 is a side elevation of a second modified form of the presentinvention;

Fig. 7 is an end view of the device shown in Fig. 6;

Fig. 8 is a side elevation partly in section of a third modification,and

Fig. 9 illustrates diagrammatically the operation of the type of deviceillustrated in Figs. 6 and 7 The cylinders of explosive engines are veryapt to become scored in operation by broken wrist pins, broken rings orby reason ofwrist pins working loose and out against the sides of thecylinder. Such scores may be satisfactorily repaired by cleaning outSpecification of Letters Patent.

- Patented Nov. 1, 1921.

Serial No. 452,868.

and properly preparing such scores and then filling the scores with asuitable hard solder as is fully described in my copending application,Serial Number453,502. It is then necessary that the solder thus insertedbe scraped off to conform with the true cy1indrical surface of thecylinder. Cylinders in use become worn so that the radius of the boregradually increases with use and it is hence particularly desirable thatan adjustable scraper be available which can be made to exactly conformto the bore of the particular cylinder which is to be repaired. Anadjustable scraper of the character indicated will obviously have ageneral application beyond the specific purpose above indicated.

The present invention involves the principle that what may be termed theeffective radius of an arc increases proportionately as the plane of thearc is inclined from the perpendicular relative to the axis of acylindrical surface. To illustrate concretely a flat scraper having anarcuate scraping edge struck on a radius of one inch will, when heldperpendicular relative to a plane surface and drawn repeatedly acrossthe same, scrape a cylindrical groove having a radius of one inch. Ifthis same scraper is inclined from the perpendicular relatively to thesaid surface to be scraped the groove scraped will have a greaterradius, proportional to the inclination of the scraper from theperpendicular, which will increase until the scraper lies perfectlyparallel with the plane surface in which position no groove at all wouldbe scraped.

Furthermore an adjustment of efiective curvature occurs where a flatscraper having an arcuate cutting edge is bent or shaped cylindricallyabout an axis parallel with the radius of curvature that bisects saidarcuate cutting edge, the effect of which operation is to incline theplane of the arcuate cutting edge relative to said axis.

Applying the principles above indicated applicant employs a scraper 11of relatively thin sheet steel which is preferably provided withoppositely disposed arcuate cutting edges 12. This may be held between abase plate 6 and a follower member 7 secured together by a nut 8 asillustrated in Fig. 8, base plate 6 being angularly adjustable relativeto a tool handle 13 by any suitable means, illustrated here as by havingbase plate 6 provided with an ear 14 adapted to be pivotally supportedas at 15 to a hinge member 16 carried by tool handle 13 and providedwith locking bolts 17. In this,the simplest type of device hereinillustrated, the scraper 11 is tilted relative to tool handle 13 whichwill be held by the operator at the most convenient angle relative tothe plane of the surface being scraped which with a skilled mechanic maybe regarded as substantially a constant.

In Figs. 6 and 7, the scraper 11 is shown secured in a holder adapted tobend it circularlyon an axis extending parallel with the cutter bladeand parallel with the chords of the arcuate cutting edges.

Figs. 1 to 4. illustrate a similar scraper 11 in a holder adapted tobend it circularly on an axisextending parallel with the cutter vblade'and perpendicular to the chords of the arcuate cutting edges.

An improved holding device adapted to adj ustably bend the cutter asdesired is illustrated herein as comprising the shank 1 having athreaded stud 2 adapted to be received into a mating socket in toolhandle 13 and further threaded as at 5 to receive base plate 6. Baseplate 6 is preferably provided with parallel flattened sides 9 androunded ends 18. A projection 3 extends from stud 1 through plate 6 andthrough a central orific-e of a follower member 7 having rounded ends 18and depending ears 10 u on its sides adapted to overhang and guide thefollower on plate 6. The end of projection 3 which extends abovefollower7 is threaded to receive an adjustment nut 8 by means of which thefollower 7 may be adjusted to or away from base plate 6. The adjacentfaces of base plate 6 and follower? are struck to substantially coaxialcylindrical surfaces extending parallel with a straight line bisectingthe axes of the cutting-edges as in Figs. 1 to 4: or parallel with thechords of the axes of the cutting edge as illustrated in Figs. 5 and 8.

By tightening or loosening nut 8 the curvature of the scraper member maybe increased or reduced as desired and as previously pointed out theradius of the are which the cutting edges 12 will cut will be modifiedin proportion with this change in the curvature of the scraper. Asimilar result will be secured by means of tilting the scraper with thedevice illustrated in Fig. 8.

It will be noted, however, that where the scraper is tilted or where itis bent on an axis extending transversely of the scraper as in Figs. 5and 6, the angle of the bevel of the cutting edge will be variedrelatively to the surface to be scraped which is not always desirable.By bending the scraper on an axis extending longitudinally thereof asillustrated in Figs. 1 to 4, a similar mains constant.

modification of the radius of the groove scraped is secured while inaddition the angle of the bevel of the cutting edge re- Experimentsfurther indicate that with the scraper thus bent, a particularlyefficient cutting action is secured decidedly superior to that obtainedwith a fiatscraper, clean cut shavings commencing adjacent the ends ofthe arcuate cutting edges and curling inwardly toward the center leavingthe scraped surface in a highly polished condition. 7

To insure scraping only the alloy inlay and not the original cylinderwall, it is desirable that scrapers intended for this work be made of asteel sufficiently hard to cut the alloy inlay and not the cast'iron ofthe cylinder.

Having thus fully tion, I claim: Y

1. In a tool for scraping cylindrical surfaces, a holder, a scraperblade having an arcuate cutting edge and means for bending said scraperblade to vary the effective are of the cutting edge with respect to thegeneral plane of the blade in the holder and the holder.

2. A tool for scraping cylindrical surfaces comprising a base plate, afollower member, the facing surfaces of said plate and follower beingstruck to substantially coaxial cylindrical surfaces, a scraper memberadapted to be interposed between the said cylindrical surfaces and meansfor described my inv'en drawing said base plate and follower tofacescomprising a base plate, a follower,

the facing surfaces of said plate and follower being struck to co-axialcylindrical surfaces, a scraper interposed'between the plate andfollower and having an arcuate cutting edge extending beyond the sameand means for drawing the plate and follower together to bend thescraper cylindrically therebetween. j

i. In a tool for scraping cylindrical surfaces, a base plate having aconvex cylindrical surface, a:follower having a concave cylindricalsurface, a fiat scraper member adapted to be received between saidsurfaces, said scraper having an arcuate cutting edge so disposedrelatively to said cylindrical surfaces that the chordiof said arcuatecutting edge is perpendicular to the ROSS D. HEAOOX.

